Bender ISOMETER isoCHA425HV User manual

Manual EN
isoCHA425HV_D00404_00_M_XXEN / 10.2020
ISOMETER® isoCHA425HV with AGH420-1
Insulation monitoring device with coupling device for unearthed DC
systems (IT systems) DC 0 V to 1000 V
Suitable for DC charging stations according to CCS or CHAdeMO
Software version: D0624 V1.xx

2 isoCHA425HV_D00404_00_M_XXEN / 10.2020
Service and support for Bender products
First-level support
Technical support
Carl-Benz-Strasse 8 • 35305 Grünberg • Germany
Telephone: [phone]
0700BenderHelp *
Fax: [phone]
E-mail: [e-mail]
Available on 365 days from 7.00 a.m. to 8.00 p.m. (MEZ/UTC +1)
* Landline German Telekom: Mon-Fri from 9.00 a.m. to 6 p.m.: 6.3 cents/30 sec.; remaining time: 6.3
cents/min.
Mobile phone: higher, depending on mobile phone tariff
Repair
Repair, calibration and replacement service
Londorfer Strasse 65 • 35305 Grünberg • Germany
Telephone: [phone] (technical issues) or
[phone], -785 (commercial issues)
Fax: [phone]
E-mail: [email protected]
Field service
On-site service
Telephone: [phone], -762 (technical issues) or
[phone] (commercial issues)
Fax: [phone]
E-mail: fi[e-mail]
Mon-Thu 7.00 a.m. to 4.00 p.m., Fri 7.00 a.m. to 1 p.m. (MEZ/UTC +1)

isoCHA425HV_D00404_00_M_XXEN / 10.2020 3
ISOMETER® isoCHA425HV with AGH420-1
Inhaltsverzeichnis
1 General instructions .........................................................................5
1.1 How to use this manual..............................................................................................5
1.2 Indication of important instructions and information ...................................5
1.2.1 Signs and symbols........................................................................................................5
1.3 Training courses and seminars.................................................................................5
1.4 Delivery conditions.......................................................................................................5
1.5 Inspection, transport and storage ..........................................................................6
1.6 Warranty and liability...................................................................................................6
1.7 Disposal of Bender devices........................................................................................6
1.8 Safety.................................................................................................................................6
2 Function...............................................................................................7
2.1 Intended use...................................................................................................................7
2.2 Device features ..............................................................................................................7
2.3 Functional description ................................................................................................8
2.3.1 RFand Cein "CHd" mode (CHAdeMO)..................................................................8
2.3.2 RFand Cein "dc" mode (CCS) ..................................................................................8
2.3.3 Fault location R% ..........................................................................................................9
2.3.4 System leakage capacitance Ce.................................................................................................................. 9
2.3.5 System voltages Un, UL1e and UL2e........................................................................................................... 9
2.3.6 Functional tests of contactors in the charging station and the vehicle...9
2.3.7 Monitoring of the insulation resistance................................................................9
2.3.8 Undervoltage/overvoltage monitoring................................................................9
2.3.9 Stop mode ....................................................................................................................10
2.3.10 Self test functions (device errors)......................................................................... 10
2.3.11 Cyclic background test.............................................................................................10
2.3.12 Continuous PE connection monitoring.............................................................10
2.3.13 User-controlled test functions............................................................................... 10
2.3.14 Internal and external test button......................................................................... 10
2.3.15 Timer for test functions............................................................................................10
2.3.16 Device test at device start.......................................................................................10
2.3.17 System connection test L1/+ and L2/-...............................................................11
2.3.18 Alarm assignment of the alarm relays K1/K2...................................................12
2.3.19 Measuring and response times.............................................................................12
2.3.20 Password protection (on, OFF).............................................................................. 13
2.3.21 Factory setting FAC ................................................................................................... 13
2.3.22 External, combined test or reset button T/R....................................................13
2.3.23 Fault memory ..............................................................................................................13
2.3.24 History memory HiS ..................................................................................................13
2.3.25 Interface/protocols.................................................................................................... 13
3 Dimensions and mounting ........................................................... 15
3.1 Dimensions...................................................................................................................15
3.2 Mounting.......................................................................................................................15

4 isoCHA425HV_D00404_00_M_XXEN / 10.2020
3.3 Wiring diagram ...........................................................................................................16
3.4 Commissioning...........................................................................................................17
4 Operation of the device................................................................. 19
4.1 Displays and buttons................................................................................................ 19
4.2 Menu overview ...........................................................................................................20
4.3 "AL" menu .....................................................................................................................21
4.3.1 Setting response value.............................................................................................21
4.4 "out" menu....................................................................................................................21
4.4.1 Relay mode configuration ......................................................................................21
4.4.2 Relay alarm assignment "r1" and "r2" and LED assignment....................... 21
4.4.3 Fault memory configuration.................................................................................. 22
4.4.4 Interface configuration ............................................................................................22
4.5 "t" menu.........................................................................................................................23
4.5.1 Time configuration.................................................................................................... 23
4.6 "SEt" menu....................................................................................................................23
4.6.1 Function configuration............................................................................................23
4.7 Measured value display and history memory .................................................24
5 Data access using the BMS protocol ........................................... 25
6 Data access using the Modbus RTU protocol............................ 27
6.1 Reading out Modbus registers from the ISOMETER®....................................27
6.2 Command of the master to the ISOMETER® ....................................................27
6.2.1 Response of the ISOMETER® to the master ......................................................27
6.3 Writing to Modbus registers (parameter setting)..........................................27
6.3.1 The master sends a command to the ISOMETER® .........................................27
6.3.2 Response of the ISOMETER® to the master ......................................................28
6.4 Exception code ...........................................................................................................28
6.4.1 Structure of the exception code........................................................................... 28
7 Modbus register assignment of the ISOMETER® ...................... 29
7.1 Device-specific data type of the ISOMETER® ................................................... 31
7.1.1 Device name ................................................................................................................31
7.1.2 Measured values.........................................................................................................32
7.1.2.1 Float = Floating point value of the channels..............................................................32
7.1.2.2 AT&T = Alarm type and test type (internal/external)...............................................33
7.1.2.3 R&U = Range and unit .........................................................................................................34
7.1.3 Alarm assignment of the relays ............................................................................ 35
7.2 Channel descriptions................................................................................................ 35
8 IsoData data string ......................................................................... 37
9 Technical data.................................................................................. 39
9.1 Standards, approvals and certifications.............................................................43
9.2 Ordering information ...............................................................................................43
9.3 Declaration of Conformity ...................................................................................... 44

isoCHA425HV_D00404_00_M_XXEN / 10.2020 5
ISOMETER® isoCHA425HV with AGH420-1
1 General instructions
1.1 How to use this manual
This manual is intended for qualified personnel working in electrical engineering and electron-
ics! Part of the device documentation, in addition to this manual, is the enclosed
"Safety instructions for Bender products".
Read the manual before mounting, connecting and commissioning the device.
Always keep the manual within easy reach for future reference.
1.2 Indication of important instructions and information
I Danger! Indicates a high risk of danger that will result in death or serious injury if not avoided.
I Warning! Indicates a medium risk of danger that can lead to death or serious injury if not avoi-
ded.
I Caution! Indicates a low-level risk that can result in minor or moderate injury or damage to pro-
perty if not avoided.
i
Information can help to optimise the use of the product.
1.2.1 Signs and symbols
Disposal Temperature range Protect from dust
Protect from mois-
ture
Recycling RoHS directives
1.3 Training courses and seminars
www.bender.de/en -> Know-how -> Seminars.
1.4 Delivery conditions
The conditions of sale and delivery set out by Bender apply. These can be obtained from Bender in
printed or electronic format.
The following applies to software products:
"Softwareklausel zur Überlassung von Standard- Software als Teil von Lieferungen,
Ergänzung und Änderung der Allgemeinen Lieferbedingungen für Erzeugnisse und
Leistungen der Elektroindustrie" (software clause in respect of the licensing of
standard software as part of deliveries, modifications and changes to general
delivery conditions for products and services in the electrical industry)
Die Elektroindustrie

6 isoCHA425HV_D00404_00_M_XXEN / 10.2020
General instructions
1.5 Inspection, transport and storage
Check the shipping and device packaging for transport damage and scope of delivery. The following
must be observed when storing the devices:
1.6 Warranty and liability
Warranty and liability claims in the event of injury to persons or damage to property are excluded in
case of:
Improper use of the device.
• Incorrect mounting, commissioning, operation and maintenance of the device.
• Failure to observe the instructions in this operating manual regarding transport, commission-
ing, operation and maintenance of the device.
• Unauthorised changes to the device made by parties other than the manufacturer.
• Non-observance of technical data.
• Repairs carried out incorrectly.
• Use of accessories and spare parts not recommended by Bender.
• Catastrophes caused by external influences and force majeure.
• Mounting and installation with device combinations not recommended by the manufacturer.
This operating manual and the enclosed safety instructions must be observed by all persons working
with the device. Furthermore, the rules and regulations that apply for accident prevention at the place
of use must be observed.
1.7 Disposal of Bender devices
Abide by the national regulations and laws governing the disposal of this device.
For more information on the disposal of Bender devices, refer to
www.bender.de/en -> Service & support.
1.8 Safety
If the device is used outside the Federal Republic of Germany, the applicable local standards and regu-
lations must be complied with. In Europe, the European standard EN 50110 applies.
I Danger! Risk of electrocution due to electric shock! Touching live parts of the system carries the risk of:
• A fatal electric shock
• Damage to the electrical installation
• Destruction of the device
Before installing and connecting the device, make sure that the installation has been de-energised.
Observe the rules for working on electrical installations.

isoCHA425HV_D00404_00_M_XXEN / 10.2020 7
ISOMETER® isoCHA425HV with AGH420-1
2 Function
2.1 Intended use
The ISOMETER® isoCHA425HV in combination with the coupling device AGH420-1 monitors the insula-
tion resistance RFfor DC fast charging stations according to CHAdeMO standard or according to
Combined Charging System (CCS) for nominal system voltage ranges between DC 0 V and 1000 V.
In order to meet the requirements of applicable standards, customised parameter settings must be
made on the equipment to adapt it to local equipment and operating conditions.
Please heed the limits of the area of application indicated in the technical data. Any use other than that
described in this manual is regarded as improper.
i
To ensure that the ISOMETER® functions correctly, an internal system resistance of ≤ 1 kΩ must exist
between L1/+ and L2/- via the source or the load.
2.2 Device features
• Monitoring of the insulation resistance RFof DC charging stations according to CHAdeMO
standard or Combined Charging System (CCS) in the system voltage range up to 1000 V
• CHAdeMO (Mode CHd):
– Detection of insulation faults in the system voltage range 50 V to 1000 V, single-pole insulation
faults RFU up to 100 kΩ with a response time of 1 s and up to 2 MΩ with a response time of 10 s
– Two-pole, symmetrical insulation faults RFS up to a maximum of 160 kΩ and with a response
time of 10 s
– Maximum system leakage capacitance 1.6 μF per conductor
• CCS (dc mode):
– Detection of insulation faults up to 2 MΩwith a response time of 10 s
– Maximum system leakage capacitance 5 μF
• Measurement of the system leakage capacitance Ce
• Measurement of the nominal system voltage Un(True RMS) with undervoltage/overvoltage
detection
• Measurement of the residual voltages UL1e (between L1/+ and earth) and UL2e (between L2/-
and earth)
• DC residual voltage
• Selectable start-up delay, response delay and delay on release
• Two separately adjustable response value ranges of 5...600 kΩ (Alarm 1, Alarm 2)
• Alarm output via LEDs ("AL1", "AL2"), a display and alarm relays ("K1", "K2")
• Automatic device self test with connection monitoring
• Selectable N/C or N/O relay operation
• Measured value indication via a multifunctional LC display
• Fault memory can be activated
• RS-485 (galvanically separated) including the following protocols:
– BMS interface (Bender measuring device interface) for data exchange with other Bender compo-
nents
– Modbus RTU
– IsoData (for continuous data output)
• Password protection to prevent unauthorised parameter changes
• Stop mode to deactivate the measuring pulse generator

8 isoCHA425HV_D00404_00_M_XXEN / 10.2020
Function
2.3 Functional description
The ISOMETER® is designed for use in DC charging stations according to CHAdeMo standard or
Combined Charging System (CCS) and can be set to the respective mode in the "SEt" menu via the
Mode parameter. It measures the total insulation resistance RFS as well as the one-sided insulation re-
sistance RFU, the system leakage capacitance Ce, the system voltage Un(True RMS) between L1/+ and
L2/- and the DC system voltages (residual voltages) UL1e and UL2e between L1/+ as well as L2/- and
earth.
Depending on the selected mode, the values RFS and RFU are combined to form the measured value RF.
In the "AL" menu, a prewarning and a main alarm limit value can be set for the measured value RF. The
prewarning limit value can only be set higher than the main alarm limit value. If the measured value
reaches or falls below the limit values, an alarm is signalled. For the measured value Un, an overvoltage
and undervoltage limit value can be enabled and adjusted, the violation of which triggers an alarm. The
limit value alarms are only deleted when the respective measured value no longer violates the limit val-
ue including the corresponding hysteresis.
All alarms generated by the ISOMETER® are signalled via the LEDs "AL1" and "AL2". In the "out" menu,
the LEDs can be assigned to the alarm relays ("K1, K2"). In addition, the operation of the alarm relays
(n.o./n.c.) can be configured and the fault memory "M" can be activated or deactivated. If the fault
memory is activated, the alarm relays remain in alarm condition and the LEDs light until the reset but-
ton "R" is pressed or the supply voltage Usis interrupted.
In the "t" menu, the start-up delay at device start, the response delay and the delay on release of the
alarms as well as the repetition time of the automatic device self test can be set.
For the RS-485 interface, the protocols BMS, Modbus RTU or isoData are selected in the "out" menu. The
measured values can be read and the parameters of the ISOMETER® can be set via the BMS protocols,
e.g. using the BMS Ethernet gateway (COM465IP) and Modbus RTU. If the isoData protocol is selected,
the ISOMETER® only sends the measured values, once per second.
The device function can be tested using the test button "T". The device parameters are set via the LC
display and via the control buttons on the front panel. This function can be password-protected.
The ISOMETER® can be set to stop mode to deactivate the measuring pulse generator.
2.3.1 RFand Cein "CHd" mode (CHAdeMO)
In "CHd" mode, the insulation fault RFand the system leakage capacitance Ceare only determined for
DC system voltages ≥ 50 V. The value RFis determined from the smaller one of the values RFU and RFS.
RFU is the one-sided insulation fault determined based on the voltages UL1e and UL2e up to a maximum
of 2 MΩ. RFS is the two-pole, symmetrical insulation fault and is only determined up to a maximum of
160 kΩ. The response time of the single-pole insulation fault RFU is 1 s for limit values up to 100 kΩ and
Un>= 100 V and 2 s above these values. For the two-pole insulation fault RFS it is 10 s.
The maximum permissible system leakage capacitance Ce is 1.6 µF per conductor.
2.3.2 RFand Cein "dc" mode (CCS)
In "dc" mode, the insulation fault RFup to 2 MΩ and the system leakage capacitance Ceare determined
independently of the system voltage. The maximum permissible system leakage capacitance in this
mode is 5 µF. The response time for RFis 10 s.

isoCHA425HV_D00404_00_M_XXEN / 10.2020 9
ISOMETER® isoCHA425HV with AGH420-1
2.3.3 Fault location R%
From Un> DC 20 V the fault location R% is calculated for two-pole insulation faults RFS up to 500 kΩ
("CHd" mode 150 kΩ). The value -100 % indicates a single-pole insulation fault at L2/-, 0 % indicates a
symmetrical insulation fault and +100 % indicates a single-pole insulation fault at L1/+. For values of 30
% and more, the alarm assignment of the relays distinguishes between insulation faults at L1/+ and L2/-
.
From the values R% and RFthe partial resistances RF+ and RF- can be calculated using the following for-
mulas:
Fault at conductor DC+ ->RF+ = (200 % * RF)/(100 % + R%)
Fault at conductor DC- -> RF- = (200 % * RF)/(100 % – R%)
2.3.4 System leakage capacitance Ce
The system leakage capacitance Ceis determined for insulation faults RF> 10 kΩ up to a value of 17 µF.
Above 12 µF, the message Device error "E.07" is displayed.
2.3.5 System voltages Un, UL1e and UL2e
The system voltage Unbetween terminals L1/+ and L2/- is measured as RMS value (True RMS). Limit val-
ues for overvoltage and undervoltage are available in the "AL" menu (see chapter " 'AL' menu"). Above
1200 V, the message "Overvoltage" is displayed regardless of the set overvoltage limit value.
The DC system voltages UL1e and UL2e are respectively measured between terminals L1/+ as well as L2/-
and earth. No limit value is assigned to them.
2.3.6 Functional tests of contactors in the charging station and the vehicle
If the ISOMETER® is disconnected on one pole from the monitored voltage source during a functional
test of the charging station or vehicle contactors, a false alarm may occur depending on the location of
an existing insulation fault. For insulation faults above 600 kΩ the false alarm can be prevented by a re-
sistor of 200 kΩ connected directly between terminals L1/+ and L2/-.
2.3.7 Monitoring of the insulation resistance
The two parameters "R1" and "R2" for monitoring the insulation resistance can be found in the response
value menu "AL" (see chapter " 'AL' menu"). The value "R1" can only be set higher than the value "R2". If
the insulation resistance RFreaches or falls below the activated values "R1" or "R2", this leads to an
alarm message. If RFexceeds the values "R1" or "R2" plus the hysteresis value, the alarm will be cleared.
2.3.8 Undervoltage/overvoltage monitoring
In the response value menu "AL" (see chapter " 'AL' menu"), the two parameters "U <" and "U >" for
monitoring the system voltage Uncan be activated or deactivated. The maximum undervoltage value is
limited by the overvoltage value. The RMS value of the nominal system voltage Unis monitored. If the
nominal system voltage Unreaches, falls below or exceeds the limit values "U <" or "U >", an alarm will
be signalled. If the maximum permissible nominal system voltage Unset for the ISOMETER® is exceeded,
an alarm message will be triggered even if the overvoltage limit value has been deactivated. The alarm
will be deleted when the limit values plus the hysteresis are no longer violated.

10 isoCHA425HV_D00404_00_M_XXEN / 10.2020
Function
2.3.9 Stop mode
For applications where the ISOMETER® is not needed and the measuring pulse interferes with other
measuring functions, it can be set to stop mode via the Modbus protocol or by pressing and holding
the external test/reset button ("T/R"). The measuring pulse generator is turned off and the measuring
function is deactivated. The message "StP" appears on the display. It sends the identifiers "warning" and
"external test" via the communication interface.
2.3.10 Self test functions (device errors)
The ISOMETER® provides test routines to check the correct function of the device. Some test routines
are performed cyclically or continuously in the background during the normal measuring function.
Other test routines are triggered by the user either cyclically via a timer (menu item "t"/"test"), the inter-
nal test button, the external test button or the communication interface (COM); the measuring function
of the device is stopped during the test period.
In case of a device error, all 3 LEDs on the device flash, the display shows the message "E.xx" according
to the error code table "Overview of some error codes" and, depending on the alarm assignment, the
relays switch.
2.3.11 Cyclic background test
The cyclic background test to check the µC is not visible to the user and does not influence the measur-
ing function. In case of malfunction, the messages Device error with error codes "E.09" to "E.16" is dis-
played.
2.3.12 Continuous PE connection monitoring
The connection of terminal "E" of the AGH420-1 to the PE protective conductor is monitored continu-
ously and in parallel with the measuring function of the device via the input "KE" of the ISOMETER®,
which is also connected to the PE protective conductor. In case of a connection interruption, the mes-
sage Device error with the error code "E.01" is displayed.
2.3.13 User-controlled test functions
The user-controlled test functions interrupt the measuring function of the device. They always include a
test of the measurement technology (device error "E.05") and additionally a system connection test
which can be activated by the user ("SEt"/"nEt" menu) to test the connection between terminals L1/+
and L2/-. If these test functions are started via a test button or the communication interface, this can be
indicated not only by the LEDs AL1 and AL2 lighting up but also by the message "test" via the relays
(menu "out"/"Alarm assignment").
2.3.14 Internal and external test button
Pressing the external test/reset button or the test button "T" on the device (> 1.5 s) starts the user-con-
trolled test functions. When pressing the test button "T" on the device, all display elements available for
this device are additionally shown.
2.3.15 Timer for test functions
At menu item "t"/"test" the user-controlled test can be activated in a cycle of one or 24 hours. The timer
restarts after each completed test, regardless of whether it was triggered by the timer or manually.
2.3.16 Device test at device start
At menu item "SEt"/"S.Ct" the execution of the user-controlled test functions can be activated for the
time of the device start.

isoCHA425HV_D00404_00_M_XXEN / 10.2020 11
ISOMETER® isoCHA425HV with AGH420-1
2.3.17 System connection test L1/+ and L2/-
The system connection test configurable in the "SEt"/"nEt" menu checks the connection between termi-
nals L1/+ and L2/- via the monitored system. For correct operation of the ISOMETER® the monitored
system must have a low-ohmic (< 1 kΩ) internal resistance. The "on" setting is used in systems where Un
< DC 100 V. When "on U" is set, the system voltage must be Un> DC 100 V during the test. If an error is
detected during this test, the message Device error system connection "E.02" is displayed. If the system
voltage Unis lower than DC -30 V during the system connection test, the message Device error reverse
polarity "E.03" is also displayed.
Overview of some error codes:
Error code Description
E.01 PE connection error
The connection of terminals E or KE to earth is interrupted.
Action:
Check connection, eliminate error.The error code will be erased automatically once the error has been eliminat-
ed.
E.02 System connection error
The internal resistance of the system is too high or the connection of terminals L1/+ or L2/- to the system is
interrupted.Terminals L1/+ and L2/- are connected incorrectly.
Action:
Check connection, eliminate error.The error code will be erased automatically once the error has been eliminat-
ed.
E.03 System connection error reverse polarity
Terminals L1/+ and L2/- are connected with reverse polarity to the monitored DC system.
Detection from Un< DC -30V.
E.05 Measurement technology error:
The measured insulation value is no longer updated due to system disturbances or a device error. At the same
time, the prewarning and main alarm for the measured insulation value are set.
Calibration invalid after software update:
In case of a software update, E.05 appears together with E.08 if the new software is no longer compatible with
the calibration of the device. Either the previous software version must be installed again or the device must be
recalibrated at the factory.
E.07 The system leakage capacitance Ceof 12 µF has been exceeded.
E.08 A calibration error was detected during the device test.
Action:
If the error continues to exist after checking the device connections, there is an error inside the device.
Internal device errors "E.xx" can be caused by external disturbances or internal hardware errors. If the
error message occurs again after restarting the device or after a reset to factory settings (menu item
"FAC") , the device must be repaired. After eliminating the error, the alarm relays switch back automati-
cally or by pressing the reset button. The self test can take a few minutes.

12 isoCHA425HV_D00404_00_M_XXEN / 10.2020
Function
2.3.18 Alarm assignment of the alarm relays K1/K2
The messages "Device error", "Insulation fault", "Undervoltage/overvoltage fault, "Device test" or
"Device start with alarm" can be assigned to the alarm relays via the "out" menu. An insulation fault is
indicated by the messages "+R1", "-R1", "+R2" and "-R2". The messages "+R1" and "+R2" indicate an insu-
lation fault assigned to conductor L1/+, and the messages "-R1" and "-R2" indicate an insulation fault as-
signed to conductor L2/-. If the insulation fault cannot be assigned to any conductor, "+Rx" and "-Rx"
are set together.
The message "test" refers to a self test manually triggered via a test button or the communication inter-
face.
The message "S.AL" indicates a so-called "device start with alarm". After connecting the supply voltage
Usand setting the parameter to "S.AL = on", the ISOMETER® starts with the measured insulation value RF
= 0 Ω and sets all activated alarms. The alarms are only cleared when the measured values are up-to-
date and no limit values are violated. With the factory setting "S.AL = off", the ISOMETER® starts without
an alarm.
i
It is recommended to set the parameter value "S.AL" identically for both relays.
2.3.19 Measuring and response times
Operating time tae
The operating time tae is the time required by the ISOMETER® to determine the measured value. For the
measured insulation value RF, the system leakage capacitance Ce, the residual voltages UL1e and UL2e as
well as the faulty conductor "R%" it depends on the insulation resistance RFand the system leakage ca-
pacitance Ce.
i
System disturbances may lead to extended measuring times. The time for the system voltage meas-
urement Unis independent of this and is considerably shorter.
Response delay time ton
The response delay time ton is set uniformly for all messages in the "t" menu using the parameter "ton",
whereby each alarm message specified in the alarm assignment has its own timer for ton. This response
delay time can be used for interference suppression in the case of short measuring times. An alarm will
only be signalled if there is a limit value violation of the respective measured value for the period of ton
without interruption. Every time the limit value is violated within the time ton, the response delay time
"ton" restarts once again.
Total response time tan
The total response time tan is the sum of the operating time tae and the response delay time ton.
Delay on release toff
The delay on release toff can be set uniformly for all messages in the "t" menu using the parameter "toff",
whereby each alarm message listed in the alarm assignment hast its own timer for toff. An alarm will
continuously be signalled until the limit value of the respective measured value is not violated (includ-
ing hysteresis) for the period of toff without interruption. Each time the limit value is not violated for the
duration of the delay on release toff, the delay on release "toff" restarts.
Start-up delay time t
After connection to the supply voltage Usthe alarm output is supressed for the preset time (0…10 s)
specified for parameter "t".

isoCHA425HV_D00404_00_M_XXEN / 10.2020 13
ISOMETER® isoCHA425HV with AGH420-1
2.3.20 Password protection (on, OFF)
If password protection has been activated (on), settings can only be made via the buttons if the correct
password has been entered (0...999).
2.3.21 Factory setting FAC
Activating the factory settings will reset all modified settings with the exception of the interface param-
eters to the default values upon delivery.
2.3.22 External, combined test or reset button T/R
• Reset = press the external button < 1.5 s
• Reset followed by a test = press the external button > 1.5 s
• Stop measuring function = press and hold the external button
The stop function can also be triggered via an interface command and in this case it can only be reset
via the interface.
Only one ISOMETER® may be controlled via an external test/reset button. It is not allowed to use a par-
allel connection of several test or reset inputs for combined testing of ISOMETER®s.
2.3.23 Fault memory
The fault memory can be activated or deactivated via the parameter "M" in the "out" menu. When the
fault memory is activated, all pending alarm messages of the LEDs and relays remain available until
they are deleted via the reset button (internal/external) or the supply voltage Usis switched off.
2.3.24 History memory HiS
When the first error occurs after clearing the history memory, all measured values (see chapter
"Measured value display and history memory") are saved in the history memory. This data can be read
out using the menu item "HiS". In order to be able to record a new data record, the history memory
must first be cleared via the menu using "Clr".
2.3.25 Interface/protocols
The ISOMETER® uses the serial hardware interface RS-485 with the following protocols:
• BMS
The BMS protocol is an essential component of the Bender measuring device interface (BMS
bus protocol). Data is transferred using ASCII characters.
• Modbus RTU
Modbus RTU is an application layer messaging protocol and it provides master/slave commu-
nication between devices that are connected altogether via bus systems and networks.
Modbus RTU messages have a 16-bit CRC (Cyclic Redundant Checksum), which guarantees re-
liability.
• IsoData
The ISOMETER® continuously sends an ASCII data string with a cycle of approximately 1 s.
Communication with the ISOMETER® within this mode is not possible and no additional trans-
mitter may be connected to the RS-485 bus cable. (See chapter "IsoData data string")
i
The IsoData protocol can be terminated by sending the command "Adr3" during a transmission
pause of the ISOMETER®.

14 isoCHA425HV_D00404_00_M_XXEN / 10.2020
Function
The parameter address, baud rate and parity for the interface protocols are configured in the "out"
menu.
i
With "Adr = 0", the menu entries "Baud rate" and "Parity" are not shown in the menu and the IsoData
protocol is activated. With a valid bus address (i.e. not equal to 0), the menu item "Baud rate" is dis-
played in the menu. The parameter value "---" for the baud rate indicates the activated BMS protocol.
In this case, the baud rate for the BMS protocol is set to 9,600 baud. If the baud rate is set unequal to
"---", the Modbus protocol is activated with a configurable baud rate.

isoCHA425HV_D00404_00_M_XXEN / 10.2020 15
ISOMETER® isoCHA425HV with AGH420-1
3 Dimensions and mounting
3.1 Dimensions
Abb. 3–1 Dimensions in mm
3.2 Mounting
Variant A: DIN rail mounting Variant B: screw mounting
The front plate cover can be opened at the lower part marked with an arrow.
90 mm
45
67,5
36 mm
31,1
47,5
70,5
2
2
&2 x
1 x
100 mm 107 mm
Click
M4
M4
!
1.
2.
3. Click!

16 isoCHA425HV_D00404_00_M_XXEN / 10.2020
Dimensions and mounting
3.3 Wiring diagram
For conductor cross sections for wiring, refer to "Technical data".
Legend
Terminal Connections
A1, A2 Connection to the supply voltage Usvia fuse:
If being supplied from an IT system, both lines have to be protected by a fuse.*
E, E, KE Connect each terminal separately to PE:The same wire cross section as for A1, A2 is to be used.
L1/+, L2/- Connection to the IT system to be monitored
Up, AK1, GND, AK2 Connect the terminals of the AGH420-1 to the corresponding terminals of the ISOMETER® isoCHA425HV.
T/R Connection for the external combined test and reset button
US
KE A1 A2
Test / Reset
Up
6 A6A
DC +
DC -
PE
UpEE
GND AK2
AK1AK1GNDAK2
L2/-
L1/+
14 24 11
K1 K2
COM465IP
RS-485
AB
R
T/R
AGHxxx
30 mm 30 mm
ON AL1AL2 k
TR
MENU
AK1 AK2GND
Up KE A1 A2
14 24 11
AT/R B
EE UP
AK2 AK1GND
L1/+ L2/-
R
on
o
AB
J-Y(St)Y 2x0,6
Un> 800 V

isoCHA425HV_D00404_00_M_XXEN / 10.2020 17
ISOMETER® isoCHA425HV with AGH420-1
Terminal Connections
11, 14 Connection to alarm relay "K1"
11, 24 Connection to alarm relay "K2"
A, B RS-485 communication interface with connectable terminating resistor. Example: Connection of a BMS
Ethernet gateway COM465IP
i
* For UL applications: Use 60/75 °C copper lines only! UL and CSA applications require the supply
voltage Usto be protected via 5 A fuses.
3.4 Commissioning
1. Check that the ISOMETER® is properly connected to the system to be monitored.
2. Connect the supply voltage Usfor ISOMETER®.
The device carries out a calibration, a self test and adjusts itself to the IT system to be moni-
tored. This procedure may take up to 40 s; afterwards, the standard display appears showing
the present insulation resistance, e.g.:
The pulse symbol signals an error-free update of the measured resistance value. If the meas-
ured value cannot be updated due to malfunctions, the pulse symbol will be hidden.
3. Starting a manual self test
Press test button "T". While pressing and holding the test button (> 1.5 s), all display elements
available for this device are shown. After releasing the button, the test starts and "tES" flashes
for the duration of the test. Detected malfunctions are displayed as error codes (see
"Overview of some error codes"). The alarm relays are not checked during the test (factory
setting).
The setting can be changed in the "out" menu, so that the relays switch to the alarm state
during the manual self test.
4. Check factory setting for suitability.
Are the settings suitable for the installation to be monitored? (For lists of factory settings, see
from chapter " 'AL' menu")
5. Check the function using a genuine insulation fault.
The ISOMETER® on the monitored system must be tested with a suitable resistance to earth.

18 isoCHA425HV_D00404_00_M_XXEN / 10.2020
Operation of the device

isoCHA425HV_D00404_00_M_XXEN / 10.2020 19
ISOMETER® isoCHA425HV with AGH420-1
4 Operation of the device
4.1 Displays and buttons
Function Device front
ON
AL1
AL2
green - on
yellow - alarm
yellow - alarm
T
Arrow-up button: navigate up in the menu.
Test button (press > 1.5 s)
By pressing and holding the test button, the display elements are shown.
R
Arrow-down button: navigate down in the menu.
Reset button (press > 1.5 s)
ENTER
MENU MENU button:
Press > 1.5 s: start menu (menu item "AL" appears) or exit menu item (Esc).
Any recent changes will not be stored.
Press < 1.5 s: conrm menu selection or conrm modied value.
Function Display
1 U : System voltage Un
R : Insulation resistance RF
C : System leakage capacitance Ce
2 Monitored conductor
3 = :Voltage type DC
: Error-free measured value update
~ :Voltage type AC
4 Measured values and units
5 Password protection activated
6 In the menu mode, the operating mode of the respective alarm relay is
displayed.
7 Communication interface with measured value: isoData operation
8 Fault memory activated
9 Condition symbols
10 Identier for response values and response value violation
i
The areas of the display that can be configured flash.
AL1 AL2
+
test onoff MAdr
L1L2 C
<
>
s
kM %
Fµ
{
{
{
{
12 3
4
567
8
{
9
{
10

20 isoCHA425HV_D00404_00_M_XXEN / 10.2020
Operation of the device
4.2 Menu overview
Measured value display Menu selection Parameter input
Menu Parameter
AL Query and set response values
out Congure fault memory, alarm relays and interface
t Set delay times and self test cycles
SEt Set device control parameters
InF Query software version
HiS Query and clear history memory
ESC Go to the next higher menu level
< 1 s
< 1 s
< 1 s
P1
. . .
Pn
ESC
> 1.5 s
> 1.5 s
AL
out
t
SEt
InF
HiS
ESC
R [kΩ]
C [
µF]
U L1 L2 [V ]
UL1 [V
]
UL2 [V
]
R [%]
UR [kΩ]
or
t > 5 Min.
< 1 s
k
R
> 1.5 s
< 1 s
> 1.5 s
> 1.5 s